Vehicle warning systems are known and used to help drivers identify potential collisions. Specifically, U.S. Pat. No. 6,472,978 to Takagi et al. discloses a system including a communication unit held by a pedestrian and a transmitter/receiver equipped on a vehicle. The communication unit and the transmitter/receiver are in communication with each other when the pedestrian is within a predetermined proximity to the vehicle. A notification can be provided to both the vehicle and the pedestrian that they are within close proximity to each other so as to help the vehicle and pedestrian avoid colliding with each other. The system may also include a roadside transmitter which receives and transmits information to the vehicle driver.
U.S. Patent Application Publication No. 2005/0107954 to Nahla discloses a collision warning avoidance system using an onboard navigation unit and a GPS interface to locate a train. At least one fixed transponder station is distributed along the train track. The trains are provided with transponders which allow a management system to track the location and movement of the transponders and notify trains when the path of another transponder indicates that there is a potential for a collision.
U.S. Pat. No. 5,983,161 to Lemelson et al. discloses a vehicle collision avoidance and warning system using GPS. Lemelson teaches using a GPS to predict a path of a vehicle and using GPS to monitor the paths of other vehicles and determine if any of the paths intersect so as to notify appropriate vehicles of a potential collision.
However, neither Takagi nor Lemelson provide responsive and timely information to vehicles. Specifically, Lemelson et al. teaches a system which requires tremendous processing capabilities to process all the different GPS information and paths of different vehicles. Further processing time is required so as to eliminate vehicles which are not within a sphere of influence of each other. Takagi et al. does not detect whether or not the person and the vehicle are heading in the same direction. Rather, Takagi just notifies a vehicle and a person of the close proximity to each other. Furthermore, Nahla is not scalable and is not adaptable to existing roadways because Nahla teaches path prediction based upon the speed and direction of a particular train along an established railway. Accordingly, it is desirable to have a system that can predict whether or not, based upon the path of two objects, there is a potential for a collision and can do so in a timely manner without all of the equipment and processing capabilities disclosed in Lemelson. It is further desirable to have a scalable and adaptable vehicle collision warning system that may be selectively implemented on roadways having a history of traffic accidents.